ProjectWithXsdExtension.php

<?php

class ProjectWithXsdExtension extends ProjectExtension {
  public function getXsdValidationBasePath() {
    return __DIR__ . '/schema';
  }
  public function getNamespace() {
    return 'http://www.example.com/schema/projectwithxsd';
  }
  public function getAlias() {
    return 'projectwithxsd';
  }

}